The Research For Protection Mechanism Based On The Clos Matrix In Optical Networks

At present, the rapid development of optical network technologies, in particular DWDM technology, as well as new fiber-optic technology, makes optical network transmission capacity has reached T bit/s and even high level. The problem of survivability for network becomes more stands out because of the huge capacity of network and real time services. Once the network failed, it will bring serious economy expense and social influence. Therefore, how to ensure the reliable business transmission has become one of the core technologies in optical network. As a core routing equipment in Optical network, the Optical Cross-Connect (OXC) plays important roles in optical network configuration and management except for its basic function of optical routing. Therefore, the reliability and efficiency of OXC decide the survivability of optical network. This paper presents a survey of the survivability mechanisms of OXC based on Clos cross-matrix for optical network. The main jobs and contributions in this paper are following three aspects:1. First the OXC based on Clos cross-matrix protection principle has been analyzed. When the network is failed, the protection routing algorithms on unicast and multicast business transmission have been realized. In order to verify the protection routing performance, the algorithm simulations are carried out by OPNet software. The results show that the size of Clos cross-matrix and the fan-out value are important factors in OXC protection performance. The larger scales of Clos cross-matrix and the greater value of fan-out, the protection algorithms have a better performance.2. The blocking performance of Clos cross-matrix and the fault character of Clos cross-matrix have been analyzed. For different types of the fault, two fault models are proposed for the next research. Simulations are carried out to test the fault model and the conclusion shows that Clos cross-matrix has higher blocking property with heavy traffic load and fault condition. In order to improve the fault tolerance performance of network, new fault tolerant algorithms are introduced and a better fault tolerance performance is proved by later simulations.3. The general Clos cross-matrix is improved to multi-links Clos cross-matrix, and the protection algorithms for new structure are proposed in order to get a good protection and fault tolerant performance. Simulation is carried out and the result shows the multi-links Clos cross-matrix has a good performance.